CIRCUIT DIAGRAM AND DESCRIPTION
TRANSMITTER AND RECEIVER FOR LAND
is used as multiplexer which
corresponding switching pulse to signal processor unit. Signal
processing unit has large signal amplifier (complementary symmetry
amplifier) and crystal oscillator for frequency signal generation and
ies used are
35.015MHz, 35.025MHz, and
and Right motio
The receiver has
radio frequency receiver (SCRX2FS),
it also has in built
signal processing unit which process the serial data received and gives to
the motor switching unit.
This switching unit has negative feedback
differential amplifier which switches corresponding motor in specified
to received signal.
TRANSMITTER AND RECEIVER FOR ARM
The transmitter circuit has parallel to serial data multiplexer (HT12E) and
RF transmitter TX02. It also has 6 push button and 8 diodes. When a push
button is pressed corresponding parallel input is given to multiplexer and
serial data output from multiple
xer is given to transmitter which transmits
The receiver circuit has serial to parallel data De
controller (89C51) and RF receiver RX02. It also has 6 swit
istors and 6 relays.
When a signal is received RX02 will give the
serial data signal to De
multiplexer (HT12D) which converts it into
parallel data. This parallel data will be given to Port1 pins of Micro
controller. The Micro
controller is pre
based on requirement
of the operation. The outputs are taken from Port3 pins of Micro
controller. These binary outputs are given to corresponding switching
transistors. This activates corresponding relay and hence drives the
specified motor in required di
3.3 AUTOMATIC LIGHT ILLUMINATION
In Automatic illumination system the LDR acts as sensor which
activates/deactivates the relay (connected to doom light) depending on
light illumination of environment.
At low light
resistance of LDR
Ohms and activates the relay to switch on doom light array. At light
illumination environment resistance of LDR drops and deactivates
The Relay used here is 6V, 1A coil and operating principle is of
omagnetic type. Connections of
can be brought out of
PCB and can be placed anywhere in robot. White LED array with polished
reflectors surrounding the LED array has good illumination.
A reverse biased germanium diode is used here as a
room temperature the reverse resistance of the diode being very high (over
), it produces no effect on transistor T1 which conducts and k
the reset pin (4) of IC1 at
‘ground level’ and so the alarm does not sound.
When temperature in the vicinity of diode D1 (the sensor) increases in case
, the reverse resistance of D1 drops.
At about 40 degree Celsius its resistance drops to a value below 1
This stops T1’s conduction and the IC’s reset pin 4 becomes positive
through resistance R2, which sounds the alarm.
HIGH SENSITIVE METAL DETECTOR
The circuit in High sensitive Metal detector works on the principle of
detecting the amplitude of a wave
form. This is called Amplitude
When a metal object is placed near the detecting coil, some of the magnetic
flux passes into the object and creates a current called
some of the magnetic flux and thus less flux is avai
lable for the
receiving secondary coil.
This produces a lower output from the coil and causes the second transistor
in the circuit to be turned OFF slightly and the voltage on the collector
This allows the third and fourth transistors to oscillate
and pass a
signal to the fifth transistor to drive a mini speaker